Gaining Limits
by AcademySenseiIruka
Summary: Iruka and Kakashi are subjected to a jutsu that will radically change their... lives? (Eventual Kakairu, don't like don't read)
1. Chapter 1: Truth is Both Cold and Hard

I am in the process of moving and since I write old school with pen and paper... well I packed all my writing away. So going threw writers withdrawal I came up with this. Hope you like it.

SIDEBAR: This is my first submitted story EVER, so please be kind.

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><p><span>Chapter 1: Truth Is Both Cold and Hard<br>

"I am so very sorry Kakashi-sensei."

"So you've said." The elite hummed in his usual bored tone. What was not usual was the subtle tension in his body as he read his usual book.

"I really didn't mean to -"

"Iruka sensei, don't" The Icha Icha novel closed with a snap. "It only makes things worse."

Kakashi had no reason to except Iruka's apology, no matter how heart felt. He had "killed" him. Nodding sadly, Iruka wandered over to the hospital window of their adjoining room. He suddenly felt homesick staring down at his home. Despite the fact that he was still in Konoha, he felt removed, alienated. And he had managed to subjected one of the most powerful ninja in Konoha to join in this misery with him. He felt sick again but from something else entirely.

He could feel Kakashi watching him, analyzing his movements. Dissecting his every motion via that brilliant brain of his.

"Mah Sensei, look I -" Weather the Copy ninja was about to apologize or not, Iruka would never know because it was at that moment the Hokage briskly entered, Shizune on her heels.

"Well brat you really managed to step in it this time." She growled. "And you! Back in bed. Its hard enough keeping him bed ridden I don't need that shit from you too."

Iruka didn't need to be told twice, he scurried over to his bed with as much professionalism as any scurrying chuunin could manage.

Pulling his bed sheets around him Iruka looked up in horror to see all three ninja smiling at his nervousness. His trade mark blush colored his face as quick as striking a match. Through the heat of his burning embarrassment he shyly returned their smiles.

Deciding to be merciful, Lady Tsunade went straight to business. "Well we've managed to make some progress in understanding the jutsu you were hit with Sensei. It appears to be a odd version of an old bloodline limit thought to be extinct." The Sannin folded her arms across her impressive chest. "One of the more bizarre facets of this kekkei genkai is its actually contagious. Which is what happened to you." She said turning to Kakashi. "It works by killing the host and making subtle changes in the body in order to function exclusively by the bloodline limit. Which requires-"

"Blood." Kakashi finished for her.

Tsunade nodded in silent confirmation. "From now on you will both require the ingestion of blood in order to continue to maintain health. We have made arrangements to have the hospital blood bank set aside a small daily supply for you, anonymously of course. At least until we figure out more about how this thing works." She mumbled the last bit more to herself knowing full well everyone in the room could hear her.

"How long will we remain quarantined?" Kakashi asked and Iruka, who had begun to wilt under the weight of the revelation, perked up.

"Well from everything we have gathered the jutsu is spread threw being bitten by someone infected. And as long as you are kept fed." unconsciously she turned to Iruka. "You wont have the desire to bite someone."

To his credit the young chuunin did such a good job hiding his guilt only two of the three caught on. But all three clearly observed his awkward trepidation when he asked...

"Will I be able to teach again?"

When Tsunade spoke, her ruff feminine voice was gentle, ominous, truthful. "I have no idea Iruka-kun."

He couldn't help but pick up on the fact that for once he was called by his name not his title. For some reason this realization stung far deeper than actually being told his position was uncertain had.

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><p>Well what do you think about chapter one? I have never even attempted to write a vampire flick before. but I have read some and came to the conclusion that being a vampire could be explained as a literal kekkei genkai.<p> 


	2. Chapter 2: Icha Icha and Pudding Cups

I just realized I forgot the customary disclaimer in the beginning of my last chapter, woops. Well I guess I said as much when I mentioned it was my first submitted story and since Naruto has been in existence for 15 years... I will count that as my disclaimer since, based on that information, you should be able to figure out I am not Kishimoto Sama. You clever reader you.

Also a special shout out to hieiashke my first ever reviewer! and to Zaeta Ketchum my first ever follower! You both are amazing thank you for your support. This chapter is for you. Hope you like it.

and to everyone who read my story thank you.

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><p><span>Chapter 2: Icha Icha and Pudding Cups<span>

Kakashi Hatake kept his clothed nose buried in his book long after Lady Tsunade had left, ignoring Iruka completely. Strangely he was ok with it. He and Kakashi had never been close despite there connection to Naruto. Now however, the two shared in a useless bloodline limit that left them dependent on a daily consumption of blood. All evidence suggested they would be forced to drink it for the rest of there... existence. And it was all thanks to him.

Blurry eyes locked unfocussed on the ceiling tiles recounting the memory of returning home. As soon as he arrived he visited the hospital to report he had been struck by an unknown jutsu and that a ninja, unaffiliated with a village, had bitten him, causing him to pass out. He had received a precautionary round of antibiotics but after being checked out, was discharged with the snide reminder that hospitals were for sick people but, should anything change, he should come in.

The slow chill that came over him was gradual enough that even he didn't notice. But Kakashi-Sensei had. It was this keen instinct and concern for a fellow shinobi that led Kakashi to investigate, and promptly be bitten by, a suddenly ravenous sensei. The only thing Iruka had to be thankful for was that he had not bitten one of his students during the week. That thought would have stopped his heart, if the jutsu hadn't already done that.

He sighed despondently.

"Would you please quit doing that? There's no point in worrying yourself to death, your already there."

Jarred from his ruminating Iruka looked up to see Kakashi had shut his book and apparently had done so some time ago. The Jounin sat on the edge of his bed facing Iruka. Hands cupped in his lap, book resting at his side.

"Besides, Lady Tsunade will eventually figure out how to deal with this and when she does we will make the necessary arrangement to continue to live our lives like we have always done. And you and I will go our separate ways like nothing ever happened." Iruka politely swallowed a bitter sarcastic retort but failed to hold off glaring daggers at the Jounin.

"You can't know that."

This time it was Kakashi who sighed despondently. "And you can't know she wont. Either way staring holes in the hospital ceiling is not going to fix this and worrying about what you should or should not have done wont ether."

Iruka glared harder, Kakashi was right. Damn him. But it didn't make not worrying any easier. Especially since he had nothing to do and no place to go.

"Maa Sensei." Kakashi chirped happily. "I'll let you read my book. Special edition." He mockingly waved the offensive reading material in front of the teacher like it was tempting. It wasn't.

"Kakashi-san," Iruka began irritably. "Despite the fact that those books are clearly a favorite of yours. I think I will pass on your offer... adamantly pass on it."

Kakashi's smile never wavered. It was the same u shaped eye smile Iruka had once become quite accustomed to seeing in the mission room, just before receiving a shoddily drawn up report.

Iruka saw it for what it was. An unwonted glimpse of an elite at play. Like a wolf playing fetch.

At first he assumed Kakashi was normally playful after missions with team seven. That he got some perverse pleasure out of messing with someone. Sussing out and exploiting a persons pet peeves, pushing buttons, testing limits and boundaries like a torture expert. But unlike Ibiki and Anko, for Kakashi, it was harmless fun. Something just to get a rise out of someone. So he never gave it much thought. But when Kotetsu commented that the jounin only ever pulled that "stunt" with him, he became intrigued. He had intended to ask about it directly but always shied away. Not wanting to discourage that spark of playfulness. It was important to him Kakashi had that. He wanted the wolf to have his chew toy. Even if he couldn't know why.

But when Sauske went away so did the teasing. It wormed Iruka more than he thought it ever would to see it again.

A knock at the door drew the attention of both sensei's to there former student, Sakura.

"Lady Tsunade asked me to come by and see how you each were doing." She explained stepping inside with the confidence of a well trained medic. She held something that looked like a white binto box.

"Maa, we're fine. Sensei and I were just discussing Make Out Paradise." The pervert quipped. Iruka's eyebrow twitched fiercely, threatening to jump off his face and assault the Jounin.

Sakura blushed deeply. "Iruka Sensei I had no idea you-"

"Sakura," He cut her off. "I have not now, nor will I ever, read that that that... thing!" He wanted to say trash. He really did but the novel was in some way significant to Kakashi. And while Iruka did not make it a habit of kowtowing to any elite, he knew this book was a fixture in Kakashi's life, as iconic as a mask and kuni. Iruka may not approve but he made sure never to call it it filth or trash. Even if it was. He believed that for Kakashi it must mean something more than what it appeared. Other wise any smutty book would do but Kakashi only ever had Icha Icha. So Iruka respected what ever that reason was by not calling it garbage.

Sakura smiled apologetically at her former academy sensei. "Of course Iruka Sensei. I don't know why I thought you would have." She scowled at her grinning jonuin sensei. "I don't know why I bothered but I made up some pudding and was hoping," she gave a humorless giggle. "If you could taste test them for me?"

If Sakura ever became a sannin Kakashi was reasonably certain she would be called the legendary bad chef. Iruka, did not know this.

"We'd love to." The naive chunin volunteered.

Sakura beamed awkwardly opening the binto.

Kakashi began to protest as a small cup and spoon were thrust into his hand.

"Don't worry I'll just turn around, Sensei." Giving Kakashi the respect entitled to him, the medic faced the far wall.

When Iruka took the first bite he was instinctively aware of the Jounin's intense focus on him. He ignored it.

The pudding was an odd consistency, very thin, but had a tangy hint of salt that topped of the sweet taste in a very pleasing way. He like it.

Several bites in Iruka could still feel the eye bearing into him from the other cot. He turned in confusion to see a clearly shocked elite. His one eye wide and disbelieving.

"What? It's good." At his words, the disbelieving component of the shocked expression morphed into something else. Fear.

Like a slow boil Iruka realized what the copy ninja must have been able to smell once the binto opened.

Blood.

"I'm sorry Sensei." Sakura's voice was low, mournful. "Lady Tsunades orders." Without turning to look at them the kunoichi left the room.

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><p>Well how was chapter 2? My second posting ever! and MUCH longer than the first. My goal is to post no less than 1,000 words per chapter and have a chapter posted at least once a week. I am thinking Wednesday and or Thursday will be my posting days. I already have completed Chapter 3 (minus the editing) as of this posting. I am holding off on posting that chapter cuz I want to make sure the story's overall continuity works as I make chapters 4 an 5. You'll figure out why when you read them.<p>

NOTICE: I wont be posting the week of Christmas but please be patient. I will post the following week. And don't worry about me not finishing this. I can't stand it when you start reading something and it doesn't have a resolution. Rest assured I will finish this. My OCD will force me too.

And thanks again for reading.


	3. Chapter 3: Vampire Blood Limit

Feedback request: If you have any vampire trait preferences (like not having a reflection or killed by a wooden stake) let me know. Also I don't know if I want them to gain special abilities or not. What do you think and what would you want the abilities to be? My goal is to make Vampire mythology fit the Naruto universe. I'm trying to make them balanced, not grossly overpowered. I want this story to feel like a head-cannon.

Also, I would like to give a big loud shout out to SunMoonKitsune for commenting, following along and being the VERY first to favorite one of my stories. You have no idea how awesome you are for that. Also thank you to Korregidora and genewarren946, for reviewing and or following. Your support is very much appreciated. Also thanks to everyone who is reading and following along anonymously I hope I will endeavor to earn your support. And I apologize for taking so long to update. (Vampires + Christmas = odd mix)

PS. I do not hold any rights to Iruka or Kakashi or any character in the Naruto franchise. You should know this cuz if I owned Naruto, I would have had WAY more KAKAIRU in the manga/anime. Now without further ado on with the show.

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><p><span>Chapter 3: Vampire Blood Limit<span>

The Hokage had told them they were going to need to ingest blood. On an intellectual level Iruka was aware of it and excepted it. But to actually consume it was something else entirely.

It churned his stomach, lurching in angry protest. Iruka had just the other day drunk Kakashi's blood. But that time he was so driven by need he didn't remember it. So it didn't count. This time it was something else. Something he tasted. Something he liked.

The cup had been removed along time ago but the chill of what he had done haunted him. He wanted to vomit. And Kakashi looked like he agreed. To dazed to talk, the two let themselves be plagued with their own disgust.

The rooms discomforting quiet was finally broken a half hour or so later with Lady Tsunade's return. With the ever faithful Shizune along side, Ton-ton tucked in her arms.

She said nothing at first. Quietly surveying her shinobi, taking note of there glum countenance.

They rested in the matching black pants and under shirts of there Shinobi uniform. Tactical gear and Hitai-ate were removed, folded, no doubt regulation style and carefully put away. Kakashi was laying down comfortably in bed, mask in place, Icha Icha closed on the bed side table. Not good. Iruka sat frozen on his bed bracing his back against the bars of the cot head board. He looked... hollow.

Clearly incorporating blood into their diet was going to take some doing.

"Was that really necessary." Kakashi said evenly.

At first glance she had completely missed it, but now she saw his cool simmer and cursed herself a fool for missing the venom of the silver haired elite. It took a lot to truly piss Kakashi off but here he was. A subtle heat from one eye, the only hint at the tumult coiled internally. The harsh juxtaposition to his lazy slouch served to highlight the power of who she was dealing with. Only his loyalty held him back. And that unnerved her.

She had known for along time Kakashi would most likely be her successor but here he was, a future Hokage, swallowing down the traitorous urge to lash out.

"It was." She spat "I know you may not like it but the kekkei genki you were both exposed to, has the ability to produce several different strains of its self. We are trying to narrow down what type it turned you into by eliminating traits known to be exhibited by certain strains."

"What do you mean?" Iruka breathed. Tsunade took a moment to reappraise him as well. He looked pale, tense, understandably so. Traces of fear had wormed there way to the surface and he unconsciously tightened his grip on the hem of his hospital bed sheets. Wide vulnerable chocolate brown eyes pleaded for a crumb of good news from his Hokage.

"Its called the Nosferatu kekkei genki," She began smoothly. "Tho when it was most prevalent in history it was referred to as the Vampire blood-line limit. The limit works by drawing chakra from blood and channeling it threw the body, generating a near constant stream that produces increased speed and strength. At the same time enhances hearing, eye sight and reflexes, all without draining from the body's own supply."

"So it increases your chakra?" Kakashi asked sitting up, his lazy slouch deceptively curious.

"It forces you to maintain a secondary supply of chakra. Even causing you to go mad with blood lust until you refill it."

Iruka jaw fell as he reflected on his insatiable thirst from the past week. Only now realizing what it meant.

"Before chakra was discovered these feats seamed miraculous and frightening." Tsunade continued not allowing Iruka to dwell in the past. "Vampires, as they were called, were both admired and feared. Some people willing let them selves become Vampires so they could gain these abilities. But once people began to learn how to harness chakra, they found they could achieve the same effect without any of the down sides of becoming a Vampire."

"Like drinking blood?" Kakashi supplied thoughtfully.

"Among other things, yes." The two ninja vampires looked at her, silently bidding her to continue.

"Like I said, different strains could result in a different type of Vampire. A different breed if you will. Tho some evidence suggests the type of Vampire is determined more so by the person who is bitten, not the "breed" of the vampire who bit them."

"In other words, just because Iruka-sensei bit me does not mean I will develop the same strain of vampire kekkei genki he does."

"Exactly. So now our aim is to narrow down the possibilities of what kind of Vampires you have become by subjecting you to various stimuli. What you experience will tell us a little more about what sort of Vampire you have become."

Kakashi's raised a silver brow at the cryptic yet clinical explanation. _Subjecting us to various stimuli_ that didn't sound good.

"And what will that do?" Iruka asked. When Tsunade raised a perplexed brow he cleared his throat and clarified. "I mean will knowing what type of vampire we are determine what kind of threat we pose to the village?" A stone faced shield rose to steel himself against any myriad of possible answers. His entire frame equally ridged.

"Iruka, being a Vampire does not change your psychology. But it's a good idea to know what line we are dealing with so we can be prepared for anything. I don't think of either of you as a threat to the security of this village. If I did you would both be in a holding cell right now, not a hospital." She let her words sink in. "Iruka you bit Kakashi because we didn't know what we were dealing with, I am not going to make the same mistake twice. The more we know about this thing the better."

Iruka nodded.

"Then what did you learn with your little pudding stunt?" Kakashi grumbled, his earlier irritation returning.

"Watch it Brat, becoming a Vampire has opened up the possibilities of some pretty nasty vulnerabilities. If you want I can test them out on you in an order T/I would prescribe for the Vampire who bit Iruka Sensei." An uneasy temperature settled as the two continued to glare. They stared fiercely, each adopting an air of dominance without so much as a twitch.

Iruka and Shizune, instinctively aware of the predatory threat remained completely still. well almost...

"W-what did happen to him?" Iruka choked out suddenly, the tense atmosphere seamed to ripple against his words, tentatively quelling the growing contention. "The Vampire who bit me."

"We're working on it." Tsunade growled out not looking away from Kakashi's challenging gaze. She matched his intensity with equal measure irritation as she bore down on the deviant subordinate till he lightly ducked his head backing down. Averting his eyes in subtle apology.

The standoff only took a matter of seconds but Iruka felt stiff with panic at witnessing the exchange. Finally he released a long appreciative gust of air before ushering in a fresh sweeping breath to his lungs. Funny, he had no idea he had held his breath until he allowed it out and in. He smiled away embarrassment and was pleased to note Shizune gave a similarly audible exhale. Ton-ton mirrored her handler but gave an additional pitiful oink.

Despite nothing actually having happened, it felt like something major had taken place.

Tsunade glowered at the now docile elite for a few heart beats more till she too relented their silent argument with a sigh.

"In answer to your question Iruka, the man who bit you is being hunted by ANBU. No word yet on his whereabouts but they are on his trail. In answer to YOUR question." obvious emphasis on the word your "Some Vampire still retain the ability to taste normal food whereas some don't. We know from the week Iruka was in the village, not knowing he had been altered, his perception of food had not changed. So his taste was intact. But some times how blood tastes to a Vampire is similarly altered."

"I am sorry Iruka Sensei." Shizune stepped forward defending her Hokage. "We felt it necessary to trick you into eating the blood because we did not want you to psychologically alter your perception of what you were eating. It was important to gauge how it really tastes to you. we knew we couldn't fool Kakashi-san because of his enhanced sense of smell. Unfortunately that means the entire experiment was directed at you."

Iruka's stomach churned at the memory and he made no attempt to hide the sour look on his face.

"But no mater the reason," Tsunade normally raspy voice was now soft, as if she regretted putting them threw the ordeal. "As your Hokage I apologize for resorting to such measures. Please don't view this as my questioning your loyalty. I am confident in you as a shinobi of Konohagakure." Her voice grew to unwavering confidence as she made the solemn declaration with a quirked smile. "I have utmost faith in the both of you."

Kakashi stretched to scratched the back of his unruly hair with a slight sigh. The disagreement forgotten. "So what did you find out?" He pressed voice low and cautious and he turned tentatively to the Chunin as if trying to read his state of mind.

"Not enough to make a definitive diagnosis but we have narrowed down the list of candidates to Vampires who still have normal taste buds yet enjoy the taste of blood." Iruka squirmed at the word "enjoy" being used in that context. Shizune noticed and offered a reassuring smile. "Unfortunately that doesn't narrow down the list all that much. On the other hand it doesn't appear we will need to depend on that sort of diagnostic method in the future." She flashed a wicked smile. "Fortunately for you, I Find the next method far more enjoyable."

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><p>YEAH Chapter 3 is up! I really hope you like it. Wow there was a lot of exposition in this chapter! But don't worry I just need to get a lot of the talking out of the way so the fun can begin! Things will pick up after this.<p>

Side note: I figured Tsunade would stop calling Iruka "Sensei" because she does not know if he will be one anymore. but Kakashi would be like F it, he is Iruka Sensei. Leading Tsunade to eventually go back to calling him Iruka sensei. :D


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